A little quick background here. A few months back, I replaced the timing belt, water pump, thermostat, radiator hoses, and had the radiator completely boiled/cleaned at a radiator repair shop. This solved an overheating issue I was having at interstate speeds, and it also allowed me to fix a previous owner's botched timing belt replacement, in which he put the belt on one tooth off.
Things have been great since then, with the temp gauge staying dead center in the middle. Until a week or so ago. These are the symptoms it is now exhibiting:
- Engine starts and warms up as normal
- Once at operating temperatures, it is fine when underway, temp gauge stays in the middle, and I have interior heat.
- When I stop (stop light, traffic, etc) The temp gauge begins to climb, and at the same time, my interior heat begins to go cool. It will gradually go completely cold if I sit idling long enough.
- The temp gauge, if I sit idling, will climb almost to the upper mark of the gauge, but not all the way to overheat.
- Once I begin moving, the temp gauge drops, and my interior heat comes back.
Coolant levels are normal and do not change.
So, what do you guys think? Water pump was replaced with an Advance Auto reman, thermostat was stock temp replacement, pretty much the only thing I didn't replace or refurb was the heater core.